2 Comments

I feel like changes like this happen all the time. Mini-evolution happens constantly. The only difference is there isn’t always someone there to point it out. I mean we’ve known that different genes display themselves in different environments. There is nothing different about these birds, they are simply expressing a different gene because the bird with the higher pitched songs couldn’t communicate as well.

You’re absolutely right. We see evidence of microevolution all the time. My favorite example is this is with the peppered moths in England. In a matter of years, these creatures changed their light coloring for a darker one when the Industrial Revolution left their trees blackened by soot. Very interesting.

As plant life began to resurge in some formerly cleared lands in California, Oregon and Washington over the course of the past 35 years, male white-crowned sparrows have lowered their whistling pitch and slowed down their long song-singing abilities so that their songs would carry better through the newer, thicker foliage.

Apparently, this is the first time ever that a person has been able to prove that bird songs can evolve in correlation with rapidly changing habitats.
It was a tedious venture, one that only the most devoted bird-lover could endure, that began with tracking down the recordings of the same and similar bird species in the areas from as far back as the 1970s. Once those were dusted off and played back, they were compared to recordings taken in recent years.

I’m sure you’ve heard many a tweeting or a twittering bird song in your lifetime, but could you distinguish between two different birds? What about two of the same species of birds? I don’t know about you, but it all sounds the same to me.

The woman and dedicated bird-lover responsible for this ground breaking news event is biologist Elizabeth Derryberry. She compared recordings of individual birds in 15 different areas with the older recordings and discovered – through what can only be speculated as super-tuned bird song sound abilities – that the musical pitch and speed of the trill portion of the sparrows’ short songs had dropped significantly.

That’s when Derryberry thought to check out some aerial pictures of the areas to see what had changed. She soon realized it was the dramatic increase in vegetation, and then discovered that areas that had remained mostly clear did not experience the same change in bird songs.

I know you’re at the end of your seat with this story at this point, but what does all this really mean for you and me? Well, this new research goes to show that acoustic and visual communications of animals change with their habitat. With the growing changes happening to our planet today – damaging deforestation, global warming, etc. – we might be seeing more of these changes happening soon.

The possible concern is presented in whether or not these potential changes would be for better or worse.

All through the evolution of bird songs…. It’s certainly something to ponder.